Is It Necessary To Set Null

[newera]

Hi guys. Is it really necessary to set the $name,$email,$gender to NULL? If they are empty, aren't they null then? Thanks!

 

if (!empty($_REQUEST['name'])) {
$name = $_REQUEST['name'];
}
else {
$name = NULL;
echo '<p class="error">You forgot to enter your name!</p>';
}

[Larry]

No, empty and null are different things. Empty in PHP can be an empty string, the number 0, or the value false. null is a non-value that's different than those.

[newera]

Thanks Sir, finding your book really helpful! I'm still a bit confused of the following. If nothing is typed into a particular input field in the form,doesn't that mean that the corresponding variable is unset and therefore Null?

[Larry]

Thanks for the nice words. No, if nothing is entered into that text input, then it's value will be an empty string, not null.

[HartleySan]

Maybe not the best analogy, but someone once said that, "'Empty' is like a burnable CD without any data on it, and 'null' is like no CD at all."

Does that help any?

[newera]

Hmm thanks Larry and HartleySan (yes, it helps). For the following piece of code, is setting the gender to NULL necessary or is it just a good programming practice? (since if gender is not set, then it automatically means its NULL) Thanks!

 

if (isset($_REQUEST['gender'])) {
$gender = $_REQUEST['gender'];
} else {
$gender = NULL;
}

[margaux]

If you are going to use $gender later in your script, you need to create it otherwise you will get an error '$gender undefined' which is not the same as $gender = NULL

[newera]

Ah I see, Thanks margaux! Another small doubt I have is on pg87, on script 3.5, shouldn't the form validation for $_POST['distance'] be using !empty function instead of isset since it's a text input ?

[HartleySan]

I don't have the book handy, but perhaps the following link will help:

http://virendrachandak.wordpress.com/2012/01/21/php-isset-vs-empty-vs-is_null/